Re: Shibaura: front axle fluid

Suggest you drain the fluid out, eye balling the amount. 3 quarts? 5 quarts?
Assuming it was full to begin, or nearly so.

This will tell you the capacity. It is sometimes difficult to hit with exact precision the capacities as stated in some spec sheets or manuals for a variety of reasons. Then begin to refill. Re-fill until the "line" is hit. Different tractors have differing methods of marking "full".

4 wheel, and if in a warmer climate, 80w90 or even udt is fine, but I like the flow rate of a semi-synthetic gear lube. 75w90 semi synthetics is affordable and readily available, even at Wally's. Best wishes.